From the NBER Reporter:
Assessing the Effects of Monetary and Fiscal Policy, by Emi Nakamura and Jón Steinsson, NBER Reporter 2015 Number 1: Research Summary: Monetary and fiscal policies are central tools of macroeconomic management. This has been particularly evident since the onset of the Great Recession in 2008. In response to the global financial crisis, U.S. short-term interest rates were lowered to zero, a large fiscal stimulus package was implemented, and the Federal Reserve engaged in a broad array of unconventional policies.
Despite their centrality, the question of how effective these policies are and therefore how the government should employ them is in dispute. Many economists have been highly critical of the government's aggressive use of monetary and fiscal policy during this period, in some cases arguing that the policies employed were ineffective and in other cases warning of serious negative consequences. On the other hand, others have argued that the aggressive employment of these policies has "walk[ed] the American economy back from the edge of a second Great Depression."1
In our view, the reason for this controversy is the absence of conclusive empirical evidence about the effectiveness of these policies. Scientific questions about how the world works are settled by conclusive empirical evidence. In the case of monetary and fiscal policy, unfortunately, it is very difficult to establish such evidence. The difficulty is a familiar one in economics, namely endogeneity. ..
After explaining the endogeneity problem, empirical evidence on price rigidity and its importance for assessing policy, structural modeling, natural experiments, and so on, they turn to their evidence:
Our identification approach is to study how real interest rates respond to monetary shocks in the 30-minute intervals around Federal Open Market Committee announcements. We find that in these short intervals, nominal and real interest rates for maturities as long as several years move roughly one-for-one with each other. Changes in nominal interest rates at the time of monetary announcements therefore translate almost entirely into changes in real interest rates, while expected inflation moves very little except at very long horizons.
We use this evidence to estimate the parameters of a conventional monetary business cycle model. ... This approach suggests that monetary non-neutrality is large. Intuitively, our evidence indicates that a monetary shock that yields a substantial response for real interest rates also yields a very small response for inflation. This suggests that prices respond quite sluggishly to changes in aggregate economic conditions and that monetary policy can have large effects on the economy.
Another area in which there has been rapid progress in using innovative identification schemes to estimate the impact of macroeconomic policy is that of fiscal stimulus.9 ... Much of the literature on fiscal stimulus that makes use of natural experiments focuses on the effects of war-time spending, since it is assumed that in some cases such spending is unrelated to the state of the economy. Fortunately - though unfortunately for empirical researchers - there are only so many large wars, so the number of data points available from this approach is limited.
In our work, we use cross-state variation in military spending to shed light on the fiscal multiplier.10 The basic idea is that when the U.S. experiences a military build-up, military spending will increase in states such as California - a major producer of military goods - relative to states, such as Illinois, where there is little military production. This approach uses a lot more data than the earlier literature on military spending but makes weaker assumptions, since we require only that the U.S. did not undertake a military build-up in response to the relative weakness of the economy in California vs. Illinois. We show that a $1 increase in military spending in California relative to Illinois yields a relative increase in output of $1.50. In other words, the "relative" multiplier is quite substantial.11
There is an important issue of interpretation here. We find evidence of a large "relative multiplier," but does this imply that the aggregate multiplier also will be large? The challenge that arises in interpreting these kinds of relative estimates is that there are general equilibrium effects that are expected to operate at an aggregate but not at a local level. In particular, if government spending is increased at the aggregate level, this will induce the Federal Reserve to tighten monetary policy, which will then counteract some of the stimulative effect of the increased government spending. This type of general equilibrium effect does not arise at the local level, since the Fed can't raise interest rates in California vs. Illinois in response to increased military spending in California relative to Illinois.
We show in our paper, however, that the relative multiplier does have a very interesting counterpart at the level of the aggregate economy. Even in the aggregate setting, the general equilibrium response of monetary policy to fiscal policy will be constrained when the risk-free nominal interest rate is constrained by its lower bound of zero. Our relative multiplier corresponds more closely to the aggregate multiplier in this case.12 Our estimates are, therefore, very useful in distinguishing between new Keynesian models, which generate large multipliers in these scenarios, and plain vanilla real business cycle models, which always generate small multipliers.
The evidence from our research on both fiscal and monetary policy suggests that demand shocks can have large effects on output. Models with price-adjustment frictions can explain such output effects, as well as (by design) the microeconomic evidence on price rigidity. Perhaps this evidence is still not conclusive, but it helps to narrow the field of plausible models. This new evidence will, we hope, help limit the scope of policy predictions of macroeconomic models that policymakers need to consider the next time they face a great challenge. ...